title: Tailgut cysts: report of two cases.
abstract: OBJECTIVE
  An illustration of the diagnosis and management of tailgut cysts.
  
  
  METHODS
  Two cases of tailgut cyst and a review of the literature.
  
  
  RESULTS
  A female patient presented with acute urinary retention with a retrorectal mass felt during rectal examination and confirmed on ultrasound and magnetic resonance imaging underwent surgical resection and histology confirmed a chronically inflamed mucoid fluid-filled cyst partly lined by non-keratinised squamous epithelium. A male patient with ureteric obstruction and a prerectal cyst found on ultrasound scan underwent computed tomography with biopsies, but without reaching a conclusive diagnosis. Surgical resection was carried out and histology showed a chronically inflamed mucoid fluid-filled cyst partly lined with columnar epithelium.
  
  
  CONCLUSIONS
  Tailgut cysts are a rare developmental abnormality arising from remnants of the embryological postanal gut. Usually presenting incidentally or with pressure symptoms in middle-aged females, tailgut cysts are often initially mistaken for other clinical entities. Magnetic resonance imaging helps to differentiate tailgut cysts from other retrorectal lesions and developmental cysts. Histologically, the cyst wall demonstrates a wide variety of epithelial types and has a malignant potential. Malignancy is difficult to rule out with imaging or biopsy.
  
  
  CONCLUSIONS
  Magnetic resonance imaging is the favoured imaging modality and surgical resection is recommended to relieve pressure symptoms, provide a definitive diagnosis and rule out malignancy.
authors.affiliation: St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, UK.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Au
authors.forename: Oliver
authors.initials: O
authors.lastname: Anderson
authors.forename: Barry
authors.initials: B
authors.lastname: Morgan
authors.forename: Lida
authors.initials: L
authors.lastname: Alarcon
authors.forename: Mark L
authors.initials: ML
authors.lastname: George
mesh_terms: D000328:Adult; D003560:Cysts / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012007:Rectum / Q000473:pathology*